This study is aimed to structure method of supporting design constructing new function by expanding design process. Focusing on concept blending that can create new concept, design process can be expand by taking function blending in process of dividing function. From this standpoint, study of "Composition-based function dividing process" is conducted. Relation of base concepts is factor to create the creative concept in concept blending. However, relation of base functions has not been focused in function blending. Therefore this study proposes the method of deciding base functions that create creative function. Often design is considered as problem solving process. So, from standpoint of problem solving we have proposed relation to create creative. Especially we have found the antonymous relation that is not seen in focusing only blending.